redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity

bridge: check brport attr show in brport_show 

[ Upstream commit 1b12580af1 ]

Now br_sysfs_if file flush doesn't have attr show. To read it will
cause kernel panic after users chmod u+r this file.

Xiong found this issue when running the commands:

  ip link add br0 type bridge
  ip link add type veth
  ip link set veth0 master br0
  chmod u+r /sys/devices/virtual/net/veth0/brport/flush
  timeout 3 cat /sys/devices/virtual/net/veth0/brport/flush

kernel crashed with NULL a pointer dereference call trace.

This patch is to fix it by return -EINVAL when brport_attr->show
is null, just the same as the check for brport_attr->store in
brport_store().

Fixes: 9cf637473c ("bridge: add sysfs hook to flush forwarding table")
Reported-by: Xiong Zhou <xzhou@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Xin Long 2018-02-12 17:15:40 +08:00 committed by Greg Kroah-Hartman
parent 71978491bb
commit 4c13e689e5
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/bridge/br_sysfs_if.c
View File

@ -235,6 +235,9 @@ static ssize_t brport_show(struct kobject *kobj,
struct brport_attribute *brport_attr = to_brport_attr(attr);
struct net_bridge_port *p = to_brport(kobj);
if (!brport_attr->show)
return -EINVAL;
return brport_attr->show(p, buf);
}